Apple Blossom Weevil (Anthonomus pomorum)
Taxonomy:
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Insecta
- Order: Coleoptera
- Family: Curculionidae
- Genus: Anthonomus
- Species: A. pomorum
Description:
The Apple Blossom Weevil (Anthonomus pomorum) is a small, reddish-brown beetle belonging to the Curculionidae family. It measures approximately 3–4 mm in length and has a distinctive elongated snout, characteristic of true weevils. The body is covered in fine scales, giving it a slightly mottled appearance, and the legs are a darker brown. The antennae are clubbed and elbowed, aiding in the detection of floral buds.
Life Cycle & Development:
The weevil has a single generation per year. Adults overwinter in sheltered locations such as bark crevices, leaf litter, or the ground near host trees. In early spring, as temperatures rise, the beetles become active and migrate to apple (Malus domestica) trees, feeding on developing buds.
After mating, females lay eggs within the flower buds, often depositing one per bud. The larvae hatch inside the bud and feed on developing flower tissues, preventing them from opening. This damage leads to the formation of characteristic “brown cap” flowers, which fail to develop into fruit. The larvae pupate inside the damaged buds, emerging as adults in early summer before seeking overwintering sites.
Host Plants:
The primary host of A. pomorum is the domestic apple (Malus domestica), but it can also affect other species within the Malus and Pyrus (pear) genera.
Damage & Economic Impact:
The Apple Blossom Weevil is considered a pest in commercial apple orchards, as its larval feeding reduces fruit yield. Severe infestations can significantly impact crop production, especially in temperate regions where apple cultivation is prominent. The “brown cap” symptom, where dried, unopened flower buds remain on the tree, is a key sign of infestation.
Control & Management:
- Cultural Control: Pruning and removing infested buds can help reduce populations. Encouraging natural predators, such as birds and parasitic wasps, may also aid in population control.
- Mechanical Control: Monitoring and early intervention using sticky traps or physical removal of adult weevils can help limit damage.
- Chemical Control: In commercial orchards, targeted insecticide applications may be used when adults first become active in spring. However, timing is crucial to avoid harming beneficial pollinators.
- Biological Control: Natural enemies, including parasitoid wasps and predatory beetles, contribute to population suppression in balanced ecosystems.
Distribution & Habitat:
The Apple Blossom Weevil is widely distributed across Europe and parts of Asia. It thrives in temperate climates, particularly in regions with established apple orchards or wild Malus species. It prefers sheltered overwintering sites such as hedgerows, woodlands, and orchard margins.
Conservation Status:
Anthonomus pomorum is not considered endangered, though it is managed as an agricultural pest in apple-growing regions. Integrated Pest Management (IPM) strategies are recommended to minimize chemical use and preserve ecological balance.
Interesting Facts:
- The weevil’s feeding damage often leads to reduced fruit set but can sometimes benefit trees by thinning excessive blooms, leading to larger, healthier fruit.
- Its elongated snout is adapted for piercing buds and laying eggs inside them.
- The “brown cap” symptom caused by larval feeding is a distinctive sign of infestation.
